Modeling Snowmelt Runoff Under CMIP5 Scenarios in the Beheshtabad Watershed

The aim of this study was to evaluate the variability of time distribution and contribution of runoff from snowmelt under the influence of climate change in the Beheshtabad Watershed, Iran, using the snowmelt runoff Model (SRM) and twenty Coupled Model Intercomparison Project phase 5 (CMIP5) for Representative Concentration Pathway 6.0 (RCP 6.0) for Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Twenty CMIP5 General Circulation Models (GCMs) for the lowest (RCP 2.6), highest (RCP 8.5) and medium ( RCP 6.0) emissions scenarios for the future periods (2011-2030 and 2046-2065) were obtained using MarkSim (http://gismap.ciat.cgiar.org/MarkSimGCM). The results showed that annual average rainfall will decrease 16.15% and 22.94% and mean annual maximum and minimum temperature will increase 1.79 degrees C and 2.89 degrees C for two future periods under RCP 6.0. The SRM variables and parameters were prepared from the Shahrekord station, and snow cover areas (SCAs) were obtained by MODIS satellite images. After the calibration and validation of SRM model, the SRM model was then run with the future data under RCP 6.0. and revealed the effects of climate change on snowmelt runoff. The results show the displacement of the monthly peak flow from April to March, and reducing the contribution of snowmelt runoff from 27.2 to 23.2% and 20.13% for two future periods. The present study confirmed the effects of climate change on future climate data and discharge and temporal pattern of snowmelt runoff.